1. Technical Field
The present invention relates to a high-temperature operating fuel-cell module using a high-temperature operating fuel-cell stack that operates at a high temperature.
2. Description of the Related Art
Fuel cells can achieve high total efficiency because even a small fuel cell has high power generation efficiency and it is possible to utilize heat such as heat generated during power generation or heat obtained by combusting off-gas discharged from a fuel cell. For example, the efficiency of a fuel cell can be improved by combusting off-gas discharged from the fuel cell by using a burner and using heat thus obtained as heat for a reforming reaction in a reforming unit. In such a case where heat of combustion of off-gas discharged from a fuel cell is used, for example, for a reforming reaction, a burner that can efficiently combust the off-gas is needed. As such a burner, the burners disclosed in Japanese Unexamined Patent Application Publication No. 2004-156895 and Japanese Unexamined Patent Application Publication No. 2003-254514 have been proposed for example.
Japanese Unexamined Patent Application Publication No. 2004-156895 discloses a burner that includes a fuel distributor comprising a plurality of fuel ejection holes for ejecting fuel gas, such as natural gas, mainly containing a hydrocarbon-based substance into a combustion space and an air ejection member disposed so as to surround the fuel distributor and comprising a plurality of air ejection holes for ejecting air into the combustion space. According to the burner disclosed in Japanese Unexamined Patent Application Publication No. 2004-156895, air is supplied from the air ejection holes in almost equal amounts, and therefore a stable flame can be formed.
Japanese Unexamined Patent Application Publication No. 2003-254514 discloses a burner for a hydrogen generation device that includes a distributor comprising an upper-stage gas ejection hole for ejecting city gas and off-gas into a combustion chamber. In this burner for a hydrogen generation device, an air ejection hole for ejecting air for combustion into the combustion chamber is formed in a side wall of the combustion chamber so as to be substantially opposed to the upper-stage gas ejection hole. In the burner for a hydrogen generation device disclosed in Japanese Unexamined Patent Application Publication No. 2003-254514, mixture of the fuel gas, off-gas and air for combustion can be promoted by collision of a jet flow of the fuel gas and the off-gas and a jet flow of the air for combustion.